初始压力对狭缝内爆轰传播特性影响的实验研究

在高度H=1 mm,宽度W=20 mm的狭缝内,实验研究了不同初始压力(P_0=10~40 k Pa)下化学恰当比的C_2H_4/O_2预混气的爆轰传播特性。采用烟迹法记录爆轰胞格结构,同时采用高速摄影捕捉火焰面。实验结果表明,随着初始压力降低,爆轰波的化学反应诱导区距离增大,壁面条件(如摩擦、导热)的影响增强,导致火焰传播的速度震荡加剧,爆轰波传播从多头模式向单头模式过渡,并可出现多次起爆或者熄爆等复杂现象。此外,稳定自持传播爆轰波的速度亏损会随初始压力降低而增大,但详细规律还需进一步研究。

Experimental Study of the Influence of Initial Pressure on the Detonation Propagation Characteristic in Narrow Gap

Influence of different initial pressures (P₀=10~40kPa) on detonation propagation of stoichiometric C₂H₄/O₂ mixtures was experimentally studied in a narrow gap with 1-mm-height and 20-mm-width. The soot film was utilized to record the detonation cell structure, and the high-speed cinematography was used to capture the flame. It can be found that the chemical reaction induction zone length of detonation increases and the influence of wall condition (such as friction and heat conduction) strengthens with the decrease of initial pressure, hence, the flame velocity fluctuation is intensified. And the detonation propagation transits from multi-head mode to single-head mode, which even can appear multiple detonation initiation or detonation failure phenomena. In addition, the velocity deficit of self-sustained detonation wave becomes larger with the decrease of initial pressure, however, the detailed variation rule needs a further study.